Greetings, bradbishop.
It appears that you've subscribed to CBS All Access/Showtime bundle. The problem is you're being directed to download the CBS All Access application in order to watch CBS Sunday Morning. We're glad to help with this.
If you can't stream or watch movies or TV shows from the Apple TV app, iTunes Store, or third-party apps - Apple Support -- From what we can determine, CBS Sunday Morning should be available to view. Since it isn't playing through the Apple TV app, use the steps in this article to see if it resolves the issue.
If the issues persists, which device are you using with the Apple TV app?
Let us know how that goes.
Take care.